The present invention relates to a device for advantageously guiding appliances to be implanted which belong to the field of medical devices, particularly for guiding artificial blood vessels.
With the recent progress of medical technique, the art enabling transvascular use of a variety of appliances such as artificial blood vessels without ventrotomy has reached the clinical stage. Specific examples of such art include a method of transferring and fixing an artificial blood vessel using a catheter which has been invented by the inventor of the instant invention and disclosed in literature A (for example, PCT/JP96/01347 which has been published with International Publication No. WO96/36387). This method includes: inserting a catheter into a human body through an inguinal artery to position the leading end thereof near an affected part in which an aneurysm or a like pathological change is present; inserting in a collapsed condition a tubular artificial blood vessel imparted with collapsible/restorable elasticity into the catheter; transferring the artificial blood vessel to a predetermined location near the affected part by the use of a transferring device or a hauling device; and releasing the artificial blood vessel from the catheter, thereby positioning the artificial blood vessel in the affected vascular part having the aneurysm.
An artery has a branched part at which a branch blood vessel extends from the main vessel. Where an aneurysm is present in such a branched part, it is impossible to apply the above method simply. In an attempt to enable a transvascular treatment for an aneurysm in such a case, the inventor of the instant invention has also proposed in the above literature a method including: forming a branched artificial blood vessel comprising a main body and a branch portion; transferring the artificial blood vessel in the main blood vessel to a branched part thereof; and drawing the branch portion of the artificial blood vessel into a branch blood vessel branching from the main blood vessel, thereby positioning the artificial blood vessel conformally to the branched configuration of the subject blood vessel.
In the latter method, the artificial blood vessel is accompanied by an auxiliary hauling device adapted to drag the branch portion of the artificial blood vessel independently when the artificial blood vessel is transferred in the main vessel to the branched part by a transferring device, and the hauling device is drawn into the branch blood vessel by catching it using a catcher inserted from the branch side and taken out of the body so as to be operated for drawing the branch portion of the artificial blood vessel into the branch blood vessel. However, if the subject main blood vessel is an artery that terminates in peripheral blood vessels such as the celiac artery, it is difficult for any appliance to reach a desired part from a surface of the body. In such a case, it becomes impossible to insert the catcher from the outside of the body or take the hauling device out of the body, thus resulting in a disadvantage that the proposed method cannot be used.
To solve the foregoing problem, the present invention provides a device for guiding a branched appliance having a tubular main body with collapsible/restorable elasticity and a branch portion with collapsible/restorable elasticity which branches from a part of the main body with its internal space communicating with the main body, which appliance has been transferred as collapsed in a main blood vessel to a branched part branching a branch blood vessel from the main blood vessel, the device being utilized in inserting the branch portion of the appliance into the branch blood vessel, characterized by comprising an operating rod inserted into the main body from a trailing open end thereof and operable for rotation by hand, a guiding rod continuously connected to the operating rod so as to be capable of turning around with rotation of the operating rod and having a leading end extending to an open end of the branch portion, and mooring means for releasably mooring the branch portion by a portion adjacent the open end thereof to the guiding rod, wherein when the main body is moved backward with the guiding rod made to assume a predetermined position by turning, the branch portion accompanying the guiding rod is capable of advancing into the branch blood vessel together with the guiding rod.
Preferred embodiments of the present invention include such an arrangement that the operating rod and the guiding rod are formed by turning up a flexible wire rod into a loop having a trailing side forming the operating rod and a leading side forming the guiding rod.
For more reliable turning of the guiding rod by the force applied to the operating rod, it is desired that the leading side and the trailing side of the loop be in contact with each other and the contact portion be fixed.
For easy removal of the wire rod after the appliance has been guided, the fixing of the contact portion is releasably made using a snare wire.
A feature such that at least a portion of the loop protrudes beyond a leading open end of the main body is effective for preventing the wire rod from receiving an unexpected flexing force.
To enhance the guiding ability of the guiding rod, it is desired that the guiding rod comprise a tube and a guiding wire retractably accommodated in the tube with its leading end protruding from a leading end of the tube.
In another aspect, the present invention provides a device for guiding an appliance comprising an operating rod inserted into the main body from a trailing open end thereof and operable for rotation by hand, a guiding rod continuously connected to the operating rod so as to be capable of turning around with rotation of the operating rod and having a leading end extending to an open end of the branch portion, and mooring means for releasably mooring the branch portion by a portion adjacent the open end thereof to the guiding rod, wherein when the main body is moved forward with the guiding rod made to assume a predetermined position by turning, the branch portion accompanying the guiding rod is inserted into the branch blood vessel together with the guiding rod.
Specific embodiments of this case include an arrangement wherein the operating rod and the guiding rod are formed by bending a flexible wire rod into a curve having a trailing side forming the operating rod and a leading side forming the guiding rod.
In this case also, the guiding rod preferably comprises a tube having a guiding wire accommodating bore, and a guiding wire retractably accommodated in the guiding wire accommodating bore of the tube with its leading end protruding from a leading end of the tube.
For simultaneous releasing of the appliance from a moored state and from a collapsed state, it is desired that a mooring wire serving also as collapsing means for maintaining the branch portion of the appliance in the collapsed state be provided. By drawing out the mooring wire, restoration of the branch portion can be accomplished simultaneously with the releasing of the appliance from the moored state.
An advantageous embodiment of the mooring means comprises a mooring wire forming an openable closed circuit in cooperation with the tube, the mooring wire being capable of mooring the branch portion when the closed circuit is formed by inserting the mooring wire into a portion of the branch portion and capable of releasing the mooring state when the closed circuit is opened by drawing the mooring wire out of the branch portion, wherein at least a portion of the mooring wire that extends from a location adjacent the mooring portion toward a trailing side of the tube is positioned out of the guiding wire accommodating bore.
Specific examples of this arrangement include: one in which the tube has a portion provided with a window exposing the guiding wire accommodating bore and a mooring wire passing portion formed on an outer periphery of the tube at a location away from the window toward the trailing side of the tube, the mooring wire being passed through the mooring wire passing portion and drawn into the guiding wire accommodating bore through the window to form the closed circuit; one in which the tube is provided with two longitudinally-spaced mooring wire passing portions attached to the outer periphery thereof through which the mooring wire is passed to form the closed circuit in cooperation with the tube; and one in which the tube is provided with two longitudinally-spaced windows exposing the guiding wire accommodating bore, and the mooring wire is drawn into the guiding wire accommodating bore through that window situated on the trailing side of the tube and drawn out of that window situated on the leading side of the tube to form the closed circuit defined by the window on the leading side and the tube. Other specific examples of the arrangement include: one in which the tube is provided with three longitudinally-spaced windows exposing the guiding wire accommodating bore, and the mooring wire is drawn into the guiding wire accommodating bore through that window situated on the trailing side of the tube, then drawn out of the tube through the intermediate window, and again drawn into the guiding wire accommodating bore through that window situated on the leading side of the tube, to form the closed circuit defined by the drawn-out portion of the mooring wire and the tube; one in which the tube comprises a pair of tube elements integrally related to each other and having respective wire accommodating bores, one bore serving as a guiding wire accommodating bore accommodating the guiding wire, the other bore serving as a mooring wire accommodating bore accommodating the mooring wire, and the tube element having the mooring wire accommodating bore is provided with a window exposing the mooring wire accommodating bore to form the closed circuit defined by the window and the corresponding tube element; and one in which the tube defines therein two wire accommodating bores separated from each other with an intermediate partition wall, one serving as a guiding wire accommodating bore accommodating the guiding wire, the other serving as a mooring wire accommodating bore accommodating the mooring wire, and the tube is provided with a window exposing the mooring wire accommodating bore to w form the closed circuit defined by the window and the tube.
The mooring means as described above is widely applicable to devices for guiding a common appliance as well as a branched appliance. Such a guiding device comprises a guiding rod, and mooring means for releasably mooring an appliance to the guiding rod, the guiding rod comprising a tube and a guiding wire retractably accommodated in the tube with its leading end protruding from a leading end of the tube, the mooring means comprising a mooring wire forming an openable closed circuit in cooperation with the tube, the mooring wire being capable of mooring the appliance when the closed circuit is formed by inserting the mooring wire into a portion of the appliance and capable of releasing the mooring state when the closed circuit is opened by drawing the mooring wire out of the appliance, wherein at least a portion of the mooring wire that extends from a location adjacent the mooring portion toward a trailing side of the tube is positioned out of a guiding wire accommodating bore.
The closed circuit can be formed in a manner similar to those described for the aforementioned branched appliance.
With the guiding device of the present invention, the appliance is transferred to a branched portion of a blood vessel by a typical method, and then the guiding rod is caused to turn around by rotating the operating rod so that the leading end of the guiding rod is positioned near the entrance of the branch blood vessel. Then, the guiding rod is inserted into the branch blood vessel by moving the appliance backward, and as the guiding rod goes forward, the branch portion of the appliance which is moored to the guiding rod by the mooring means is guided into the branch blood vessel. For this reason, there is no need to take any operating member or the like in and out of the branch blood vessel from the terminating side thereof. Thus, the present invention can effectively be applied to the case where it is difficult for any appliance to reach a desired location from a body surface because of the subject blood vessel terminating in peripheral vessels in an internal organ like the celiac artery. Particularly where the appliance is an artificial blood vessel and the branch blood vessel branches downstream from the main blood vessel such as the celiac artery, the guiding device of the present invention can smoothly guide the branch portion of the artificial blood vessel into the branch blood vessel since the branch portion is moved toward the branch blood vessel when the branched appliance is moved backward from the branched part of the subject blood vessel.
If the flexible wire rod is configured into a loop, the leading end of the wire is directed backward, i.e., toward the downstream direction. This feature enables the leading end of the wire rod to be readily positioned as facing opposite to the opening of the branch blood vessel, while forming the operating rod and the guiding rod using a single member. Further, the guiding rod can turn around effectively by the rotative force applied to the operating rod.
In this case, if the contact portion of the loop is fixed, the rotative force applied to the operating rod is directly converted into a turning operation of the guiding rod through the fixed contact portion while transmission of the rotative force merely as a rotative force through the loop to the guiding rod is prevented. Such transmission would otherwise occur if the contact portion is not fixed. Thus, this feature enables more reliable transmission of rotational torque.
If the contact portion of the loop is fixed using the snare wire, the looping can be released easily after the guidance of the appliance has been accomplished, and the guiding device can be particularly effectively withdrawn from the branched part in a compactly collapsed fashion.
If at least a portion of the loop protrudes beyond the leading open end of the main body, it is possible to effectively reduce the danger of bending the loop undesirably as compared with the case where the loop is forcibly made within the narrow main body.
Where the guiding rod comprises a tube and a guiding wire, it is possible to insert first the guiding wire into the branch blood vessel and then the tube accompanied by the branch portion of the appliance thereinto under the guidance of the guiding wire. With this feature, it is possible to locate the entrance of the branch blood vessel by utilizing the flexibility of the guiding wire even when the guiding wire is fairly remote therefrom, thereby effectively enhancing the ability to guide the branch portion of the appliance into the branch blood vessel.
The guiding device of the present invention may be arranged such that the branch portion of the appliance is guided into the branch blood vessel by moving the appliance forward instead of moving it backward. This arrangement makes no difference from the arrangement designed to guide the appliance into the branch blood vessel by moving it backward in that there is no need to take any operating member in and out of the terminating side of the branch blood vessel. Thus, this arrangement also can effectively be applied to the case where it is difficult for an appliance to reach a desired location from a body surface because of the subject blood vessel terminating in peripheral blood vessels in an internal organ like the celiac artery.
When the guiding device comprises a wire rod, the operating rod and the guiding rod can be formed by merely curving the wire rod.
In this case also, by forming the guiding rod comprising a tube and a guiding wire, the ability to guide the branch portion to the branch blood vessel can be enhanced effectively.
If the mooring means has an additional function as collapsing means for collapsing the branch portion of the appliance, releasing the mooring means also causes the branch portion to be released from the collapsed state at the same time thereby allowing elastic restoration of the branch portion. Thus, the branch portion of the appliance once positioned at a desired location can achieve appropriate restoration through a series of operations.
If the mooring means mainly comprises a mooring wire forming a closed circuit in cooperation with the tube, this arrangement is simple and can reliably release the branch portion by only drawing the mooring wire from a remote location to open the closed circuit even when an intermediate portion is led around as curved in the subject blood vessel. Thus, a reliable transvascular treatment can be ensured. Further, since the trailing side of the mooring wire is positioned out of the guiding wire accommodating bore, the mooring wire is assuredly prevented from being inconveniently tangled with the guiding wire, while at the same time the mooring function and the guiding function can be rendered compatible with each other on the tube.
When the closed circuit is formed in each of the modes described above, the openable closed circuit of a simplified structure can assuredly realized using the mooring wire. Particularly where the tube is provided with a window and a mooring wire passing portion for insertion of the mooring wire, it is only required that the window be formed by punching a hole in a desired portion of the tube, and the mooring wire passing portion is formed by, for example, tying the tube with a string. Where the tube is provided with two mooring wire passing portions, it is only required that the two mooring wire passing portions be formed by tying desired portions of the tube with strings. Where the tube is provided with two or three windows, it is only required that holes be punched in desired portions of the tube. Alternatively, where the tube comprises two tube elements or the tube defines two wire accommodating bores, the mooring wire and the guiding wire can be assuredly parted from each other thereby preventing interference with each other.
It should be noted that the guiding device of the arrangement comprising a guiding rod, and mooring means for releasably mooring any type of appliance including an artificial blood vessel to the guiding rod, the guiding rod comprising a tube and a guiding wire retractably accommodated in the tube with its leading end protruding from a leading end of the tube, exhibits mooring and guiding abilities similar to those described above.